I have a big system of linear equations $f_i(x_1,...x_n)$ with $n$ variables and $n$ equations. I want to extract the matrix $M$ where $\vec{f}(\vec{x})=M\vec{x}$. For example if I have
$$
f_1(x) = x ...

Starting with Mathematica and working with matrices, I am looking for a way to construct a new matrix B from columns of matrix A.
For example, matrix a has 8 columns and 4 rows, I want matrix B to be ...

Cross-posted at the Wolfram community forum
I have found this code on a forum, apparently it worked in a previous version of mathematica. Now when I run it, it keeps running for ages. I am not able ...

I believe mathematica uses some techniques beyond our book. According to the text book it is not possible to solve eigenvalues of which the matrix has not completely eigenvectors, or of those matrix ...

I'm trying to reduce to a minimum the time of some matrix operations.
When I don't parallelize and write the code in the most compact form I get the operation done in around 1sec (is this good? the ...

I am trying to graphically display a distance matrix with similar elements visually clustered into groups.
My original matrix has the elements in a random order so the first thing I do is to change ...

As we know, there are only $\frac{n(n+1)}{2}$ variables in a symmetric $n$-dimensional semi-definite matrix. Is it possible to produce a $n$-dimensional semi-definite matrix whose trace is $1$ using ...

I am interested in the following problem in combinatorics $\Cap$ Probability. Let $\lambda \in \mathbb{N}$ be a parameter. Consider a matrix of $2^\lambda$ rows and $2^\lambda$ columns. Each column ...

I wish to compute the pseudo inverse of rectangular (or square) matrices by the cubically method of Chebyshev given by $X_{k+1}=X_k(3I-AX_k(3I-AX_k))$ where $X_0=\frac{1}{\|A\|_F^2}A^*$. The procedure ...

I have solved some equations and exported the final results, which they are several Matrices, as a EXCEL file ( .Xls ). Now, I want to use these EXCEL files as my inputs to solve some other equations. ...

I want a function to take a polynomial from a list, plug a certain matrix T into that polynomial, and return the answer as another matrix. My program uses the applyPoly function suggested by a user in ...

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